Solve Equivalent Resistance: Points A and B

[physicsed]

Homework Statement

https://www.physicsforums.com/attachment.php?attachmentid=11955&stc=1&d=1197437955

Find the equivalent resistance between points A and B shown in the link above

Homework Equations

for parallel, equivalent resistance is =1/R1 +1/R2 +1/R3...
equivavalent resistance for series is = R1 + R2 + R3

The Attempt at a Solution

i believe they are all parallel or R3, R4, R5, and R6 are series becouse they depend on each other

 

[physicsed]

1/R= 1/1.5 + 1/2.5 + 1/4.3 +1/3.3 + 1/8.1 +1/6.3 =1.88
r=.53 ohm. this is not correct. the back of my book says .838 and can someone tell me how they got that answer

 

[marcusl]

First find the parallel resistance of R3, R4 and R5, call it maybe R'. Now you see that R1, R2 and the series combination (R'+R6) are in parallel. That will give you the answer.

 

[AROD]

when can you say that the voltage in the loop will be zero? not in this case?

 

[Redbelly98]

The voltage around any loop is zero, but that is not needed here. This problem can be solved using series and parallel rules for combining resistors.